Main Memory: Main memory also is known as RAM stands
for Random Access Memory. It is circuits that require continuous
electrical power in order to maintain its information and if power will
be lost then all information will be lost. It is expensive than hard
disk drive but faster than the hard disk. it within motherboard near CPU
and look like a game chip.
On your *BIOS main memory refers to the RAM. Also known as random access memory. These are the slots on your motherboard that requires modules to be inserted in order for BIOS to boot into any system. Both read and write queries are sent through the RAM. The purpose of this memory is to allocate the memory for hardware interaction and the operating systems I/O buffer. In the absence of hard disk, the RAM is often used as a buffer memory to boot into Live USB or Live CD/DVD discs. Linux live USB images makes use of main memory primarily to use the OS even in the absence of the HDD. Almost every operating system requires RAM in order for it to boot into desktop or command prompt. Also BIOS doesn't allow further I/O processing in absence of RAM.
Cache Memory: Cache memory is within CPU, it works like a buffer in Computer system. It stores data in KB and recent activities that are done by CPU. it reduces the access time to fetch data from the main memory. CPU always first look for data in cache memory and if not present in the cache then get from the RAM. Cache is more expensive than RAM, stores small amount of data but it is very fast in the processing cycle because ' data transfer ' part is absent.
This memory unit is typically built into motherboard and CPU. If you check the box of the CPU it refers to the specific cache memory from 256 onward for modern processors. Operating system like Linux and Unix also maintain their own set of cache memory during the boot for I/O requests. In case of motherboard it comes with fixed set of it's own cache memory. You can get the information about motherboards cache memory inside BIOS. The functionality of this memory is to make quicker read write requests than the RAM. Your operating system makes use of this memory for loading some I/O modules quicker to access.
Virtual Memory: Virtual memory is a different thing than RAM and Cache. It is a feature of the operating system. In simple words, if your Computer's RAM is full and has no space to start a new task, in that main time CPU transfers data from RAM to Hard disk and creates some temporary virtual space in the RAM. Virtual memory is an inbuilt feature of OS or hardware, no cost for this Memory.Every operating system allocates specific portion of HDD for the virtual memory. Windows allocates around 100-400 MB space for virtual memory by default. In case of UNIX and Linux it allows specific portion of memory for virtual memory. In case of UNIX and Linux this memory is known as "Swap memory". This memory is part of software allocation and it is not physical memory module. So it is called as Virtual memory.
Simple difference in between each memory unit can be explained as main memory is used by BIOS and CPU to communicate with the other devices inside operating system. Cache memory fills the gap of physical memory for quicker I/O requests. And virtual memory is used when the main memory and cache memory fall short for writing large number of I/O requests. It is upto the operating system to make use of each of the memory in order to operate it's desktop or the command line access for read write access to various devices.
It is also known as System BIOS, ROM BIOS, PC BIOS etc.
The main function of Basic Input Output System (BIOS) is to initialize and test all hardware components attach to the computer and load the part of operating system. BIOS also provide a medium which facilitates the application programs and operating system to interact with the keyboard, display and other I/O devices.
Following is a list of activities performed by BIOS:
Thanks
Happy Computing !
On your *BIOS main memory refers to the RAM. Also known as random access memory. These are the slots on your motherboard that requires modules to be inserted in order for BIOS to boot into any system. Both read and write queries are sent through the RAM. The purpose of this memory is to allocate the memory for hardware interaction and the operating systems I/O buffer. In the absence of hard disk, the RAM is often used as a buffer memory to boot into Live USB or Live CD/DVD discs. Linux live USB images makes use of main memory primarily to use the OS even in the absence of the HDD. Almost every operating system requires RAM in order for it to boot into desktop or command prompt. Also BIOS doesn't allow further I/O processing in absence of RAM.
Cache Memory: Cache memory is within CPU, it works like a buffer in Computer system. It stores data in KB and recent activities that are done by CPU. it reduces the access time to fetch data from the main memory. CPU always first look for data in cache memory and if not present in the cache then get from the RAM. Cache is more expensive than RAM, stores small amount of data but it is very fast in the processing cycle because ' data transfer ' part is absent.
This memory unit is typically built into motherboard and CPU. If you check the box of the CPU it refers to the specific cache memory from 256 onward for modern processors. Operating system like Linux and Unix also maintain their own set of cache memory during the boot for I/O requests. In case of motherboard it comes with fixed set of it's own cache memory. You can get the information about motherboards cache memory inside BIOS. The functionality of this memory is to make quicker read write requests than the RAM. Your operating system makes use of this memory for loading some I/O modules quicker to access.
Virtual Memory: Virtual memory is a different thing than RAM and Cache. It is a feature of the operating system. In simple words, if your Computer's RAM is full and has no space to start a new task, in that main time CPU transfers data from RAM to Hard disk and creates some temporary virtual space in the RAM. Virtual memory is an inbuilt feature of OS or hardware, no cost for this Memory.Every operating system allocates specific portion of HDD for the virtual memory. Windows allocates around 100-400 MB space for virtual memory by default. In case of UNIX and Linux it allows specific portion of memory for virtual memory. In case of UNIX and Linux this memory is known as "Swap memory". This memory is part of software allocation and it is not physical memory module. So it is called as Virtual memory.
Simple difference in between each memory unit can be explained as main memory is used by BIOS and CPU to communicate with the other devices inside operating system. Cache memory fills the gap of physical memory for quicker I/O requests. And virtual memory is used when the main memory and cache memory fall short for writing large number of I/O requests. It is upto the operating system to make use of each of the memory in order to operate it's desktop or the command line access for read write access to various devices.
*BIOS: Basic Input Output System
BIOS stand for Basic Input Output System. It is built-in software. It is the first software run by the computer when you turned on your computer system. This software is usually stored in Read Only Memory (ROM) and located on the motherboard. In modern computer systems, the BIOS contents are stored in a flash memory. It is not possible for an operating system to continue without BIOS as it is the BIOS that loads the drivers of the hard disk and primary portions of the operating system like MBR, FAT, GPT etc, into the memory to enable the operating system to continue loading itself.It is also known as System BIOS, ROM BIOS, PC BIOS etc.
The main function of Basic Input Output System (BIOS) is to initialize and test all hardware components attach to the computer and load the part of operating system. BIOS also provide a medium which facilitates the application programs and operating system to interact with the keyboard, display and other I/O devices.
Following is a list of activities performed by BIOS:
- BIOS handles the power management and initialize registers.
- It checks and loads the device drivers and interrupts handlers to the RAM.
- It is used to display system settings.
- BIOS specifies the devices that are Bootable.
- BIOS initializes the Bootstrap sequence.
Thanks
Happy Computing !
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